1. Field of the Invention
The present invention relates to soil plug release apparatus.
2. Description of the Prior Art
In the horticultural field seedlings are grown in compartmentalised trays generally of plastics material with one seedling per compartment.
In such trays the compartments are arranged in rows and columns and at the base of each compartment is a drainage hole to allow excess water to escape. When the tray is placed on a sand bed water can enter through the hole to supply the seedling.
When the seedlings have reached a desired size after weeks or months growing they need transplanting either directly into the open or into the larger seed trays or pots. Over a period of time as each seedling grows in the soil or potting compost, the soil or potting compost settles and becomes bound by the root growth of the seedling to form a solid plug which adheres to the walls of the compartment to a different extent in each compartment.
It has been previously proposed to loosen these plugs in their compartments prior to extraction for replanting. Once loosened the seedling can be grasped by the stem and removed from the tray without unduly stressing the plant. A particular scheme proposed comprises using a board bearing a plurality of pins laid out in rows and columns in an array which matches the array of drainage holes in the container. By locating the pins into the drainage holes and pushing them into the tray the soil plugs become loosened.
This arrangement has proved unsatisfactory for a number of reasons. Firstly the problem of accurately aligning all the pins with all the drainage holes simultaneously is not always easy. The tolerances to which the holes are produced in the seed tray are generally fairly wide and so it is not always possible to align the pins with the holes. Even where it is possible, each pin does not always loosen the plug it engages but sometimes tears the heart or centre out of the plug and so destroys the root system of the seedling. Also the pins become readily distorted and when this happens the deplugging operation cannot be performed satisfactorily.
It is an object of the invention to provide improved soil plug release apparatus.